Lenses and range

[docphotog]

Hey everyone, I was wondering how one can figure out the effective range of a lens. For example for canon's 17-85 mm, I was told that it has an equivalent range of 27-136 mm- how do you get that and why is that so?

I was also wondering how the value in mm equates to actual distance that lens can shoot in either feet, yards w/e. The more I think about it, the more it seems like picking a lens for a particular photo is like picking the right club for a golf shot!!

 

[AlexColeman]

Equivalent: View on a 35mm camera

What you are talking about is focusing distance.

 

[docphotog]

Flickr Photo Download: Focal Lengths - Part 4

hmmm

Flickr Photo Download: Focal Lengths - Part 2

pretty neat

 

[Ptyler22]

There is one of those ^ on the Tamron site as well, but it's interactive and you can zoom in and out